A dislocated shoulder is an injury in which your upper arm bone pops out of the cup-shaped socket that's part of your shoulder blade. The shoulder is the body's most mobile joint, which makes it susceptible to dislocation.

If you suspect a dislocated shoulder, seek prompt medical attention. Most people regain full shoulder function within a few weeks. However, once you've had a dislocated shoulder, your joint may become unstable and be prone to repeat dislocations.

Dislocated shoulder signs and symptoms may include:

A visibly deformed or out-of-place shoulder

Swelling or bruising

Intense pain

Inability to move the joint

Shoulder dislocation may also cause numbness, weakness or tingling near the injury, such as in your neck or down your arm. The muscles in your shoulder may spasm from the disruption, often increasing the intensity of your pain.

When to see a doctor

Get medical help right away for a shoulder that appears dislocated.

While you're waiting for medical attention:

Don't move the joint. Splint or sling the shoulder joint in its current position. Don't try to move the shoulder or force it back into place. This can damage the shoulder joint and its surrounding muscles, ligaments, nerves or blood vessels.

Ice the injured joint. Applying ice to your shoulder can help reduce pain and swelling by controlling internal bleeding and the buildup of fluids in and around your shoulder joint.

The shoulder joint is the most frequently dislocated joint of the body. Because it moves in several directions, your shoulder can dislocate forward, backward or downward, completely or partially, though most dislocations occur through the front of the shoulder. In addition, fibrous tissue that joins the bones of your shoulder can be stretched or torn, often complicating the dislocation.

It takes a strong force, such as a sudden blow to your shoulder, to pull the bones out of place. Extreme rotation of your shoulder joint can pop the ball of your upper arm bone out of your shoulder socket. Partial dislocation — in which your upper arm bone is partially in and partially out of your shoulder socket — also may occur.

A dislocated shoulder may be caused by:

Sports injuries. Shoulder dislocation is a common injury in contact sports, such as football and hockey, and in sports that may involve falls, such as downhill skiing, gymnastics and volleyball.

Trauma not related to sports. A hard blow to your shoulder during a motor vehicle accident is a common source of dislocation.

Falls. You may dislocate your shoulder during a fall, such as from a ladder or from tripping on a loose rug.

Males in their teens or 20s, a group that tends to be physically active, are at highest risk of shoulder dislocation.

Complications of a dislocated shoulder may include:

Tearing of the muscles, ligaments and tendons that reinforce your shoulder joint

Nerve or blood vessel damage in or around your shoulder joint

Shoulder instability, especially if you have a severe dislocation or repeated dislocations, which makes you more prone to re-injury.

If you stretch or tear ligaments or tendons in your shoulder or damage nerves or blood vessels around your shoulder joint, you may need surgery to repair these tissues.

Depending on the severity of the injury, your family doctor or the emergency room physician may recommend that an orthopedic surgeon examine the injury.

What you can do

You may want to jot down the following:

Detailed descriptions of the symptoms and the precipitating event

Information about past medical problems

All medications and dietary supplements you take

Questions you want to ask the doctor

For a dislocated shoulder, some basic questions might include:

Is my shoulder dislocated?

What tests do I need?

What treatment approach do you recommend? Are there alternatives?

How long will it take for my shoulder to heal?

Will I have to stop participating in sports? For how long?

How can I protect myself from re-injuring my shoulder?

What to expect from your doctor

Your doctor might ask you questions, such as:

How did you injure your shoulder?

How severe is your pain?

What other symptoms do you have?

Can you move your arm?

Is your arm numb or tingling?

Have you dislocated your shoulder before?

What, if anything, seems to improve your symptoms?

What, if anything, appears to worsen your symptoms?

During the physical exam, your doctor will inspect the affected area for tenderness, swelling or deformity. An X-ray of your shoulder joint will show the dislocation and may reveal broken bones or other damage to your shoulder joint.

Dislocated shoulder treatment may involve:

Closed reduction. Your doctor may try some gentle maneuvers to help your shoulder bones back into their proper positions. Depending on the amount of pain and swelling, you may need a muscle relaxant or sedative or, rarely, a general anesthetic before manipulation of your shoulder bones. When your shoulder bones are back in place, severe pain should improve almost immediately.

Surgery. You may need surgery if you have a weak shoulder joint or ligaments and tend to have recurring shoulder dislocations despite proper strengthening and rehabilitation. In rare cases, you may need surgery if your nerves or blood vessels are damaged.

Immobilization. Your doctor may use a special splint or sling for a few days to three weeks to keep your shoulder from moving. How long you wear the splint or sling depends on the nature of your shoulder dislocation and how soon the splint is applied after your dislocation.

Medication. Your doctor might prescribe a pain reliever or a muscle relaxant to keep you comfortable while your shoulder heals.

Rehabilitation. After your shoulder splint or sling is removed, you'll begin a gradual rehabilitation program designed to restore range of motion, strength and stability to your shoulder joint.

If you have a fairly simple shoulder dislocation without major nerve or tissue damage, your shoulder joint likely will improve over a few weeks, but you'll be at increased risk for future dislocation. Resuming activity too soon after shoulder dislocation may cause you to injure your shoulder joint or to dislocate it again.

Try these steps to help ease discomfort and encourage healing after being treated for a dislocated shoulder:

Apply ice then heat. Putting ice on your shoulder helps reduce inflammation and pain. Use a cold pack, a bag of frozen vegetables or a towel filled with ice cubes for 15 to 20 minutes at a time. Do this every couple of hours the first day or two.

After two or three days, when the pain and inflammation have improved, hot packs or a heating pad may help relax tight and sore muscles. Limit heat applications to 20 minutes at a time.

Maintain the range of motion of your shoulder. After one or two days, do some gentle exercises as directed by your doctor or physical therapist to help maintain your shoulder's range of motion. Inactivity can cause stiff joints. In addition, favoring your shoulder for a long period can lead to frozen shoulder, a condition in which your shoulder becomes so stiff you can barely move it.

Once your injury heals and you have good range of motion in your shoulder, continue exercising. Daily shoulder stretches and a shoulder-strengthening and stability program can help prevent a recurrence of dislocation. Your doctor or a physical therapist can help you plan an appropriate exercise routine.

To help prevent a dislocated shoulder:

Take care to avoid falls

Wear protective gear when you play contact sports

Exercise regularly to maintain strength and flexibility in your joints and muscles

Once you've dislocated your shoulder joint, you may be more susceptible to future shoulder dislocations. To avoid a recurrence, follow the specific strength and stability exercises that you and your doctor have discussed for your injury.

Questions and answers about shoulder problems. National Institute of Arthritis and Musculoskeletal and Skin Diseases. http://www.niams.nih.gov/Health_Info/Shoulder_Problems/default.asp. Accessed June 30, 2014.

Reprint Permissions

A single copy of these materials may be reprinted for noncommercial personal use only. "Mayo," "Mayo Clinic," "MayoClinic.org," "Mayo Clinic Healthy Living," and the triple-shield Mayo Clinic logo are trademarks of Mayo Foundation for Medical Education and Research.